Choosing the Appropriate Stress Test:

Brett C. Stoll, MD, FACC

February 24, 2018

Choosing the Appropriate Stress Test:

Does it Really Matter?Brett C. Stoll, MD, FACC

February 24, 2018

Conflicts of Interest

• No conflicts of interest

Objectives

• Be able to list the indications and contraindications for stress testing.

• Appreciate the different modalities available for cardiac stress testing.

• Appropriately select the optimal cardiac stress test for each patient.

Stoll’s Words of Wisdom …

• Don’t stress patients you think you might kill with the study

• Don’t order a study if you already know the answer

• If a patient can’t exercise, don’t order an exercise study

• If the patient’s resting EKG is abnormal, something other than “EKG imaging” is needed to make it a useful study

• LBBB and paced rhythms may cause false positive studies in tests that increase HR (exercise or dobutamine stress)

More Words of Wisdom …

• Echo imaging is only useful if you can image the endocardium

• Dobutamine can induce arrhythmias (AF, VT, VF)

• Adenosine, Persantine, Lexiscan can induce bronchospasm

• Stress tests are not perfect

Case StudyA 60 yo man is evaluated for chest pain of 4 months’ duration. He describes

the pain as sharp, located in the left chest, with no radiation or associated symptoms, that occurrs with walking one to two blocks and resolves with rest. Occasionally, the pain improves with continued walking or occurs during the evening hours. He has hypertension. Family history does not include cardiovascular disease in any first-degree relatives. His only medication is amlodipine.

On physical examination, he is afebrile, blood pressure is 130/80 mHg, pulse rate is 72/min, and respiration rate is 12/min. BMI is 28. No carotid bruits are present, and a normal S1 and S2 with no murmurs are heard. Lung fields are clear, and distal pulses are normal. EKG showed normal sinus rhythm w/ LBBB.

Case Question

• Which of the following is the most appropriate diagnostic test to perform next?

a. Adenosine nuclear perfusion stress test

b. Coronary angiography

c. Echocardiography

d. Exercise treadmill

General Overview

• Stress testing is generally a safe procedure

• Commonly performed (1998 Medicare data)

• Treadmill 533,000

• Stress Echo 354,000

• Stress SPECT 1,362,000

• Low risk of MI or death (1 per 2500)

• Requires appropriate supervision

Indications

Who to stress?

• Screening for obstructive CAD

• Symptoms suggesting angina (low to moderate risk)

• Acute chest pain

• Known CAD with change in clinical status

• Assessment of prognosis and severity of disease

Indications

Who to stress?

• Valvular heart disease

• New heart failure or cardiomyopathy

• Chronic left ventricular dysfunction and CHD (who are candidates for revascularization)

• Selected arrhythmias

• Undergoing non-urgent non-cardiac surgery

Contraindications

Who NOT to stress?

• Unstable angina (high risk)

• Acute myocardial infarction (< 6 days)

• Known severe LM disease

• Arrhythmia with hemodynamic instability

• Aortic dissection

Contraindications

Who NOT to stress?

• Symptomatic (critical) aortic stenosis

• Decompensated heart failure

• Severe HTN (SBP > 220 mmHg, DBP > 120 mmHg)

• Pulmonary embolism

• Myocarditis, Pericarditis

Who should get a stress test??

Bayes’ Theorem

p(X|A)*p(A)p(A|X) = ______________________

P(X|A)*p(A) + p(X|~A)*p(~A)

Given some phenomenon A that we want to investigate, and anobservation X that is evidence about A, we can update theoriginal probability of A, given the new evidence X.

Fundamentals of Stress Testing

Fundamentals of Stress Testing

Positive

Negative

Fundamentals of Stress Testing

Positive

Negative

Fundamentals of Stress Testing

Positive

Negative

Fundamentals of Stress Testing

Positive

Negative

Fundamentals of Stress Testing

Positive

Negative

Fundamentals of Stress Testing

Pre-Test Probability

ACC/AHA GuidelinesLow probability - <10% - no further testing, except for prognostic information

Intermediate probability - 10-90% - non-invasive testing for diagnosis (exercise ECG as first modality)

High probability - >90% - noninvasive testing for prognosis/management prior to cardiac cath

Pre-Test Probability

Age Nonanginal pain Atypical angina Typical angina

Men Women Men Women Men Women

30-39 4% 2% 34% 12% 76% 26%

40-49 13% 3% 51% 22% 87% 55%

50-59 20% 7% 65% 31% 93% 73%

60-69 27% 14% 72% 51% 94% 86%

Definitions of Chest Pain

• Typical angina (definite)• Substernal chest discomfort with characteristic quality and

duration

• Provoked by exertion or emotional stress

• Relieved by NTG or rest

• Atypical angina (probable) – meets 2 of the above

• Non-anginal chest pain – meets 1 or none of the typical characteristics

Pre-Test Probability

Age Nonanginal pain Atypical angina Typical angina

Men Women Men Women Men Women

30-39 4% 2% 34% 12% 76% 26%

40-49 13% 3% 51% 22% 87% 55%

50-59 20% 7% 65% 31% 93% 73%

60-69 27% 14% 72% 51% 94% 86%

But which test to order ??

Anatomy of a Stress Test

• Each cardiac stress test has two components:

• Stressing agent: treadmill, dobutamine, or adenosine (or persantine or regadenosine)

• Imaging agent: EKG, echo, or radionuclide tracer (thallium or technetium)

Stress Agents

Stressor Pro ConTreadmill Physiologic, simple,

less expensive, good for patient who can walk

Avoid in patients with SSS or pacemaker

Dobutamine No exercise needed Caution in patients with arrhythmias

Adenosine/Regadenosine(or dipyridamole)

No exercise needed; uncomfortable for some

Adenosine may induce bronchospasm – caution in COPD and asthma!!

Stress Agents

Stressor Pro ConTreadmill Physiologic, simple,

less expensive, good for patient who can walk

Avoid in patients with SSS or pacemaker

Dobutamine No exercise needed Caution in patients with arrhythmias

Adenosine/Regadenosine(or dipyridamole)

No exercise needed; uncomfortable for some

Adenosine may induce bronchospasm – caution in COPD and asthma!!

Stress Agents

Stressor Pro ConTreadmill Physiologic, simple,

less expensive, good for patient who can walk

Avoid in patients with SSS or pacemaker

Dobutamine No exercise needed Caution in patients with arrhythmias

Adenosine/Regadenosine(or dipyridamole)

No exercise needed; uncomfortable for some

Adenosine may induce bronchospasm – caution in COPD and asthma!!

Imaging AgentsImaging Pro ConEKG Simple, less

expensiveLess information. May not be able to localize the lesion. Cannot use if there are baseline EKG abnormalities i.e. LBBB, ST-T changes

Echocardiogram Good if patient has pre-existing EKG abnormalities. More info than EKG. Less expensive than nuclear.

Operator dependent to some extent. May have poor windows due to body habitus. Pre-existing wall motion abnormalities may make interpretation more challenging.

Thallium or technetium Localizes ischemia and infarcted tissue.

Expensive, Radiation exposure

Imaging Agents

EKG

Imaging Agents

EKG - LBBB

Imaging Agents

EKG - Paced Rhythm

Imaging Agents

EKG - Abnormal Baseline

Imaging AgentsImaging Pro ConEKG Simple, less

expensiveLess information. May not be able to localize the lesion. Cannot use if there are baseline EKG abnormalities i.e. LBBB, ST-T changes

Echocardiogram Good if patient has pre-existing EKG abnormalities. More info than EKG. Less expensive than nuclear.

Operator dependent to some extent. May have poor windows due to body habitus. Pre-existing wall motion abnormalities may make interpretation more challenging.

Thallium or technetium Localizes ischemia and infarcted tissue.

Expensive, Radiation exposure

Imaging Agents

Echocardiographic

Imaging Agents

Echocardiographic

Imaging AgentsImaging Pro ConEKG Simple, less

expensiveLess information. May not be able to localize the lesion. Cannot use if there are baseline EKG abnormalities i.e. LBBB, ST-T changes

Echocardiogram Good if patient has pre-existing EKG abnormalities. More info than EKG. Less expensive than nuclear.

Operator dependent to some extent. May have poor windows due to body habitus. Pre-existing wall motion abnormalities may make interpretation more challenging.

Thallium or technetium Localizes ischemia and infarcted tissue.

Expensive, Radiation exposure

Imaging Agents

Nuclear

Sensitivity and Specificity

Sensitivity SpecificityExercise EKG 68% 77%

Stress Echo 76% 88%

Nuclear Imaging 79-92% 73-88%

Selecting Modalities

Selecting Modalities

Selecting Modalities

Selecting Modalities

Selecting Modalities

Case StudyA 60 yo man is evaluated for chest pain of 4 months’ duration. He describes

the pain as sharp, located in the left chest, with no radiation or associated symptoms, that occurs with walking one to two blocks and resolves with rest. Occasionally, the pain improves with continued walking or occurs during the evening hours. He has hypertension. Family history does not include cardiovascular disease in any first-degree relatives. His only medication is amlodipine.

On physical examination, he is afebrile, blood pressure is 130/80 mHg, pulse rate is 72/min, and respiration rate is 12/min. BMI is 28. No carotid bruits are present, and a normal S1 and S2 with no murmurs are heard. Lung fields are clear, and distal pulses are normal. EKG showed normal sinus rhythm w/ LBBB.

Case StudyA 60 yo man is evaluated for chest pain of 4 months’ duration. He describes

the pain as sharp, located in the left chest, with no radiation or associated symptoms, that occurs with walking one to two blocks and resolves with rest. Occasionally, the pain improves with continued walking or occurs during the evening hours. He has hypertension. Family history does not include cardiovascular disease in any first-degree relatives. His only medication is amlodipine.

On physical examination, he is afebrile, blood pressure is 130/80 mHg, pulse rate is 72/min, and respiration rate is 12/min. BMI is 28. No carotid bruits are present, and a normal S1 and S2 with no murmurs are heard. Lung fields are clear, and distal pulses are normal. EKG showed normal sinus rhythm w/ LBBB.

Case Question

• Non-cardiac, Atypical or Typical chest pain?

• Pretest probability (60 y.o. / Male)?

• Can he exercise? Yes or No

• Interpretable resting EKG (LBBB)? Yes or No

• Lung Disease or Obesity (BMI 28)? Yes or No

65-72%

Case Question

• Which of the following is the most appropriate diagnostic test to perform next?

a. Adenosine nuclear perfusion stress test

b. Coronary angiography

c. Echocardiography

d. Exercise treadmill

Take-Home Points• Know the contraindications for stress testing

• Stress testing is generally indicated for patients with intermediate pre-test probability

• Positive test in a low-risk population is frequently false positive

• Testing in high-risk populations may help determine prognosis

• Each stress test has two components: an imaging modality and a stress modality

• When determining which stress test to order, keep in mind the patient’s ability to exercise and whether any confounding variables are present

Yes …ordering the proper stress test does matter !!

Questions ???

Presenter

Presentation Notes

Questions?